A launcher that fires a weighted bola — two 200-gram tungsten spheres connected by 1.5 meters of braided steel cable — at a fleeing target's legs. The bola wraps around the target's legs at shin height, the cable locks against itself via a ratchet mechanism, and the subject goes down. The BL-5 fires its payload at 40 m/s, giving the bola enough rotational energy to wrap tightly even against a sprinting target, and the ratchet lock prevents the cable from loosening once wrapped.

Zheng-Dao designed the BL-5 for fugitive apprehension — the classic problem of stopping a running person without shooting them. The bola solution is ancient, but the engineering is modern: the tungsten weights are precisely balanced, the cable is rated for 500 kg, and the ratchet mechanism adds a technological cruelty to a primitive concept. Once the bola is locked, it cannot be removed without a key tool that only the operator carries. The target remains immobilized until someone chooses to release them.

The BL-5's impact dynamics are classified as less-lethal, but the tungsten weights striking a target's shins at 40 m/s deliver impacts that frequently cause bone fractures. The weapon stops people from running by making it impossible for them to walk. Zheng-Dao's marketing materials describe the BL-5 as a 'mobility denial tool.' The targets describe it as getting their legs broken by a machine.